Search for interpulses in a complete sample of pulsars at a frequency of 111 MHz

An interpulse search was carried out in a sample of 96 pulsars observed on the Large Phased Array (LPA) radio telescope in the Pushchino Multibeams Pulsar Search (PUMPS). The pulsar sample is complete for pulsars having a signal-to-noise ratio (S/N) in the main pulse (MP) greater than 40. To search for weak interpulses (IP), the addition of average profiles over an interval of up to 10 years was used. Interpulses were detected in 12 pulsars (12.5% of the sample), of which 7 pulsars have an interpulse located near the 180◦ phase relative to the main pulse (probable orthogonal rotators), and 5 have phases far from 180◦ (probable coaxial rotators). The amplitude ratios of IP/MP are in the range of 0.004−0.023, the median value is 0.01. Estimates of the observed number of coaxial and orthogonal rotators with IP/MP ≥0.01 do not contradict the model according to which, during evolution, the magnetic axis and the axis of rotation become orthogonal.